1. Field of the Invention
This invention relates to an air compressor having a tilting disc which is actuated in waveform by an eccentric shaft, which is adapted to produce a high efficiency of compressed air.
2. Description of the Prior Art
It is well known that a vacuum pump comprising a plurality of blades mounted on a rotor is to be used at a pressure on the order of 1-3 kg/cm.sup.2 as required. However, the aforementioned pump has some shortcomings in that large friction heat, surface wear and fracture occur due to the long distance over which friction for unit rotation, so high speed operation is almost impossible and the life is very short.
A piston type of air compressor comprising a crank and piston may be used as required at a pressure of over 3 kg/cm.sup.2. Air volume in a cylinder is reduced in proportion to the pressure at a top dead center of the piston, and when the piston is moving downward to such air in the cylinder, the air of the clearance volume is expanded to the interior of the cylinder and fresh air fills the remainder of the cylinder. In this case, the maximum pressure of the compressor corresponds to the compression ratio. Under the maximum pressure, since the volume of air which may be discharged is zero, the compressor cannot change it to the energy of compressed air for necessary work so that a prime motor which drives the compressor is subjected to overload. In this case the efficiency of the compressor is zero.
Namely, since the volume of air remaining in the cylinder is increased to remain in proportion with the pressure, when the pressure is equal to the compression ratio the volume of air in the cylinder is maximum, thereby fresh air cannot enter the cylinder. Now the efficiency of the compressor is minimum or zero. If a discharge pressure increases from minimum or zero to maximum, the efficiency is changed from maximum to minimum so that total efficiency is not more than 50%. Therefore a volume of air corresponding to pressure for use remain in the cylinder, which leads to a loss of efficiency. Compressed air is discharged only when the piston is moving upward, and the discharge time of the compressed air is at when a rotation angle of the crank shaft is less than a certain angle, which equals 180.degree. minus an angle of raising the pressure to pressure for use, so this leads to a pulsation of pressure. In order to eliminate the pulsation phenomenon, the compressor has to comprise a plurality of piston-cylinder assemblies. And in order to supply compressed air constantly, it is necessary to provide a storage tank for compressed air. In this case, since the remaining air does not circulate, the compressor tends to be damaged by heat generated therein. And, in this known compressor, because it has a complex and bulky structure, mechanical loss is increased and considerable noise is produced.